The NuMA-related Mud protein binds Pins and regulates spindle orientation in Drosophila neuroblasts

Abstract

Asymmetric cell division generates cell diversity during development1,2 and regulates stem-cell self-renewal in Drosophila and mammals3,4. In Drosophila, neuroblasts align their spindle with a cortical Partner of Inscuteable (Pins)–Gαi crescent to divide asymmetrically, but the link between cortical polarity and the mitotic spindle is poorly understood. Here, we show that Pins directly binds, and coimmunoprecipitates with, the NuMA-related Mushroom body defect (Mud) protein. Pins recruits Mud to the neuroblast apical cortex, and Mud is also strongly localized to centrosome/spindle poles, in a similar way to NuMA. In mud mutants, cortical polarity is normal, but the metaphase spindle frequently fails to align with the cortical polarity axis. When spindle orientation is orthogonal to cell polarity, symmetric division occurs. We propose that Mud is a functional orthologue of mammalian NuMA and Caenorhabditis elegans Lin-5, and that Mud coordinates spindle orientation with cortical polarity to promote asymmetric cell division.

Cite this article

Siller, K., Cabernard, C. & Doe, C. The NuMA-related Mud protein binds Pins and regulates spindle orientation in Drosophila neuroblasts. Nat Cell Biol 8, 594–600 (2006). https://doi.org/10.1038/ncb1412

View full text

>> Full Text:   The NuMA-related Mud protein binds Pins and regulates spindle orientation in Drosophila neuroblasts